Deep venous thrombosis of the lower extremity: US evaluation.

The sensitivity of duplex ultrasonography (US) for detecting deep venous thrombosis of the lower extremity was compared with that of venography in a prospective study of 54 patients. Doppler analysis of the common femoral vein and US imaging of the deep venous system from the common femoral vein to the popliteal vein was performed. Common femoral vein response to the Valsalva maneuver was recorded. Sonographically visible thrombi and abnormal vein compressibility were 91% sensitive for the common femoral vein, and 94% sensitive for the superficial femoral or popliteal veins, with no false-positive examinations. Abnormal Doppler flow and abnormal response of the common femoral vein to the Valsalva maneuver enabled thrombi to be detected only in the common femoral and iliac veins. Combined data allowed accurate diagnoses in all patients with deep venous thrombosis proximal to the deep calf veins. US should be the screening examination of choice for evaluating patients with suspected lower extremity deep venous thrombosis.